I was having a conversation that made me go "damn the Romans for using up all the herbal birth control." Normally I'm not interested in doing time travel because I am too queer, loud, non-binary, woman coded, etc. to not get some sort of societal consequence in most of history. Also I like modern medicine and such. But, it got me thinking about how it'd be cool to be able to bring a large silphium plant back from before it went extinct.

Obviously I have no idea of the efficacy of silphium for medicinal purposes but it would be super cool to be able to grow it, sequence the DNA, and try to reintroduce it, even if only in gardens. And maybe it's actually even effective medically.

So what would you bring back?

Caveats:

• You must be able to carry the thing
• The thing will not age when traveling forward in time but you'll be able to demonstrate that you brought it from the past.
• It should be one "thing." If that "thing" is made up of multiple smaller things (not atoms ಠ⁠_⁠ಠ)... Well, if you're trying to loophole then you're on thin ice, but if a reasonable case could be made, then make it and let your fellow Tildese judge you.
• You can't bring anything back in time besides yourself, your clothes and your time machine remote control button.
• You cannot bring a person to the present. An animal that you personally can carry, and that will let you carry it, is up to you.
• ˗ˏˋ Bonus Style Points ˎˊ˗ (there are no points) for presenting your historical artifact in old timey Victorian gentleman inventor/traveler/archaeologist fashion, should the mood take you.

My 5-year-old loves doing “science experiments” at home with me and her older siblings, but it seems that the online lists of experiments we’re choosing from are truncated to leave off all but the least dangerous activities. This makes sense for a lot of low-parental-involvement contexts, but I’m going to be directing and deeply involved in these experiments. And I want fire. Smoke. Sparks. I want to make these experiments feel adventurous so the kids get really excited about whatever we’re learning. Baking soda and vinegar volcanoes and elephant toothpaste just don’t cut it.

What experiments can you recommend using only relatively common household materials? Chemicals, candles, electricity, a stovetop, etc. (Assume that the experimenters will all be taking standard precautions, wearing PPE, and generally using the experiments as both an opportunity to learn about science and about the safety measures that go with science experimentation.)

Or if you know of any websites listing these more spectacular home science experiments, please share those as well.

Bonus if the experiments involve multiple possible outcomes that the kid can use pen and paper and elementary math to predict in advance.

I have a quandary.

Suppose there is a coin that, when flipped, it lands head’s side up on a table.

Without picking the coin up to confirm the side that is down is tails. Could you ever know that it is tails ?

Assume in this world that the coin has a heads side and tails side when held in your hand.

Assume you cannot view the coin’s two sides in any other way than picking it up.

Is this just a variation of Schrödinger’s Cat ? Or is it more “does a tree make a sound if no one is around to hear it” ?

I am looking for practical ways to prove the Earth is round using materials accessible to the average person. I have zero interest in disproving Flat Earth folks.

I am inspired by Dan Olson's (Folding Ideas) excellent video where he is able to do this measuring the curvature of a lake near his home that has a very specific geography that lends itself to this sort of experiment. I've seen all sorts of ways to prove this measuring shadows and poles, using gyroscopes, etc. and wanted to know if there are any practical guides for proving once and for all that the Earth is round for yourself relying on nothing more than experimentation.

What I'm not looking for:

• Math relying on flight times/charts
• Video/picture evidence
• Deductive proofs built on agreed upon premises
• Expensive tests
• Extremely time consuming projects
• Underwhelming results (relying on a probabilistic argument for a round Earth from the evidence.)

What I am looking for:

• Practical experiments
• Things I could potentially do without spending much money
• Tests that aren't largely comprised of accepting someone else's research
• Potentially math-heavy evidence
• Results that are strong and conclusive

I've thought of finding some easy to test version of Eratosthenes' proof using two poles. I've also thought about using a balloon and sending something to space like what is done in this Tom Scott video. Nothing seems well documented in such a way as for me to be able to follow it at home.

TL;DR: I think it would be a meaningful experience to have the power to prove the Earth is round by myself, for myself. I can only compare this desire to the desire a child with a telescope has when wishing to observe Saturn or Mars themselves for the first time. It's not to prove anything or to settle doubts, but for the personal value of independently observing this astronomical fact oneself.